docs: def longest_utterances_per_container(self):
          """ Return a tuple/list containing the length of the longest utterance of ever container. """
          lengths = []
  
          for cnt in self.containers:
              longest_in_container = 0
              for utt_idx in self.utt_ids:
                  utt_length = cnt._file[utt_idx].shape[0]
                  longest_in_container = max(utt_length, longest_in_container)
  
              lengths.append(longest_in_container)
  
          return lengths